The publication of proof-of-concept exploit code affecting Internet Explorer 6 and 7 over the weekend prompted Microsoft (NSDQ: MSFT) on Monday to issue a Security Advisory. Microsoft says that it is investigating the reported vulnerability, which affects Internet Explorer 6 Service Pack 1 on Microsoft Windows 2000 Service Pack 4, and Internet Explorer 6 and Internet Explorer 7 on Windows XP, Windows Server 2003, Windows Vista, and Windows Server 2008.